This may have been posted before. But here's something I've found to make the hairline look really natural when using ST-30.

Now, I apply the tape to directly to the base ( I use all French lace). And when I do the hairline, I cut the tape in half, lengthwise...and I use two halves, meeting at the center of the hairline. This gives me thin tape that can follow the line I want to make. Here's the important part: when I lay the tape down on the hairline, I run it one "mesh row" behind the outermost edge of the base.

So when I fix the syrup, the outer row of mesh holes are not taped down, but what I think happens is that they curve down and cover the edge of the ST-30 when you press the base down on your head. Really, you can't see where the edge of the ST-30 is, even if you are looking for it. And you can't see the base that you don't put tape under because there isn't that much, and what's there is sticking to that edge.

Of course, you don't want to put the tape too far behind the hairline...or too far forward of it. But after working with it, you'll find out what I'm talking about and know the right amount.